Non-encapsulated Haemophilus influenzae are frequently isolated from the sputum of patients with chronic bronchitis but the role of these organisms in the pathogenicity of this disease is poorly understood. The purpose of this proposal is to study the macromolecular and ultrastructural characteristics of a wide range of non-encapsulated H. influenzae to attempt to identify cell wall constituents which may be associated with virulence. This will be accomplished through the following specific aims: 1) outer membrane protein patterns of 200 strains of non-encapsulated H. influenzae will be determined by SDS-PAGE and an appropriate serotype system established. 2) A lipopolysaccharide serotyping system will be established initially using alkaline digested LPS isolated from 25 H. influenzae strains and antisera made to these strains. After specific LPS types are identified the remaining 175 strains will be screened by IFA. Strains which fail to type will be studied for potentially new serotypes. 3) One hundred strains of non-encapsulated H. influenzae freshly isolated from sputa will be studied by transmission electron microscopy after negative straining for the presence of pili. 4) An organ culture model will be established using both hamster tracheal rings and human bronchial tissue obtained at surgery. These models wil be studied; a) with representative strains of each outer membrane and LPS serotype to determine if differences in adherence and invasion can be observed. b) to determine if piliation enhances attachment and if non-piliated strains can attach to the organ culture model. c) to determine whether previously diseased bronchial tissue is more susceptible to H. influenzae attachment and invasion than normal tissue. d) to determine if prior infection of the hamspter tracheal model with mycoplasms or influenzae virus enhances attachment and invasion by H. influenzae. e) to determine if pathologic changes induced in the bronchial organ culture model by viable organisms can be induced by outer membrane proteins and lipopolysaccharide isolated from these strains. f) to determine if monoclonal antibody to the H. influenzae cell surface constituents can prevent attachment, invasion and toxicity after infection in the tracheal organ culture model.